30 to 40mm E3D Fan Adapter for ANET A8 E3DV6 BMD Direct Drive X Carriage

This is my somewhat amateur remix of the 30 to 40mm fan adapter originally designed by Core3D_Tech. Ufortunately, when fitted to the lovely BMG Direct Drive Carriage (by Richard90) the fan adapter does not clear the extruder servo which causes the fitting to be pushed and slop at an angle.

My solution to this was extruding as little as possible toward the top, creating a 90 degree angle which would clear the servo motor. There were some problems encountered along the way which made this remix surprisingly difficult…

Please take notice:

The original adapter was not threaded and did not match the original E3D heatsink bracket’s thread size. I changed them to fit an M2.5 screw and adjusted the female threads with a small negative (-) tolerance to the inside faces so they could be printed better and still work with a metal M2.5 Machine Screw. For the 40mm part of the adapter, female threads were also created for an M3.5 screw and a similar process was applied.

For my printer, I am using an 40x20mm FLX Noctua Fan which is probably the quietest thing you can get away with for higher temperature prints while still maintaining good air-pressure & disbursement. Due to the the thickness of the fan, the Noctua requires at least a 20mm long screw for it to clear the depth of the mounting sockets. Finding an M3.5×20(ish) sized screw would be rather difficult and take time to order so I just made one that can be printed instead.

The flat-head screw, if you decide to use it, has a positive tolerance of +0.9mm on the male threads to counter the negative tolerances originally added to the 3.5mm female threads. Since I used these custom 3D-printed screws for this remix, I cannot confirm whether or not the tolerances for the 3.5mm female threads are too little or too much right now.

IF you decide on using a metal screw instead, please note that the depth cannot be greater than 24-25mm (on the shaft itself) or it will obstruct the right angle that is flush to the servo on the carriage. The ones I have designed have 23mm long threads and include an unusually thick head so they do not strip as easily when using a screwdriver.

The adapter itself has an O shape from the inside and spreads out. This meant that when cutting from the top to match the servo’s profile, it would create a hole along the inside which would have to be manually patched up. Since I could not get patched walls to slice correctly, I settled on having a very thin wall on the inside of the adapter that is just enough to close the hole. You can see this in one of the photos from the underside of the adapter and how it looks different from the opposing reflected side. This may have some small impacts on aerodynamics, but for all intensive purposes it works great and is not observable after installation.

I recommend printing with the lowest nozzle height you can get away with and a very slow speed. It will help with the resolution and accuracy of the printed threads. My A8 plus is still not 100% calibrated, but I printed at 20mm/sec with a 0.12mm layer height on and just left it running overnight with some pretty good looking results.

If you appreciate my efforts and work on this remix, please hit that like button and share!